Astragalus membranaceus therapy in patients with spinocerebellar ataxia type 3

Spinocerebellar ataxia type 3 (SCA3) is the most common form of hereditary cerebellar ataxia. The insulin/insulin-like growth factor 1 (IGF1) system (IIS) has been proposed as a potential target for disease-modifying therapy. Astragalus membranaceus (AM) may modulate the IIS pathway and reduce neurodegeneration, as indicated by plasma neurofilament light chain (NfL), a biomarker of disease progression.

A randomized, triple-blind, placebo-controlled crossover trial was conducted in 32 patients with SCA3. Participants received AM or placebo for three months, followed by a one-month washout, then crossed over to the alternate treatment. Plasma NfL and IIS-related markers were measured. Twenty-three participants completed the trial.

Intention-to-treat analysis revealed a modest within-treatment reduction in NfL levels (27.6 ± 10.7 vs. 25.6 ± 9.8 pg/mL, P = 0.040) and increased insulin (12.5 ± 15.2 vs. 21.1 ± 15.5 μIU/mL, P = 0.004) after AM. However, the adjusted regression model showed no significant between-treatment difference in NfL (P = 0.127), and changes in NfL were not correlated with insulin. No significant changes were observed in IGF1 or IGF-binding proteins. Exploratory subgroup analyses suggested larger biomarker changes in later-stage patients. No carryover effects or demographic differences were noted. Overall, AM administration was associated with modest within-treatment biomarker changes in NfL and insulin, although the adjusted between-treatment difference in NfL was not statistically significant. These findings should be interpreted cautiously as preliminary and hypothesis-generating observations rather than confirmatory evidence of therapeutic efficacy.